Replies

Ancient Greenland was actually green! [07/05/2007]
...sometime between 450,000 and 800,000 years ago, much of Greenland was especially green and covered in a boreal forest that was home to alder, spruce and pine trees, as well as insects such as butterflies and beetles.
Fossil DNA Proves Greenland Once Had Lush Forests; Ice Sheet Is Surprisingly Stable [07/05/2007]
Ancient Greenland was... covered in conifer forest and, like southern Sweden today, had a relatively mild climate. Eske Willerslev, a professor at Copenhagen University, has analysed the world's oldest DNA, preserved under the kilometre-thick icecap. The DNA is likely close to half a million years old, and the research is painting a picture which is overturning all previous assumptions about biological life and the climate in Greenland... large parts of Greenland were covered by forest. This was discovered by analysing fossil DNA which had been preserved under the kilometre-thick icecap. The DNA-traces are likely close to 450,000 years old, and that means that Greenland was also covered in a large ice sheet 125,000 years ago during the earth's last warm period, Eem. This was while the climate was 5 degrees warmer than the interglacial period we currently live in... Several projects... have been drilling through the icecap on Greenland, and collected complete columns of ice all the way from the top to the bottom. The ice has annual layers and is a frozen archive of the world's climate... Eske Willerslev, who is the world's leading expert in extracting DNA from organisms buried in permafrost.... "We have found grain, pine, yew and alder. These correspond to the landscapes we find in Eastern Canada and in the Swedish forests today. The trees provide a backdrop from which we can also ascertain the climate since each species has its own temperature requirements. The yew trees reveal that the temperature during the winter could not have been lower than minus 17 degrees Celsius, and the presence of other trees shows that summer temperatures were at least 10 degrees"... Furthermore Willerslev found genetic traces of insects such as butterflies, moths, flies and beetles... He analysed the insects' mitochondria, which are special genomes that change with time and like a clock can be used to date the DNA. He also analysed their amino acids which also change over time. Both datings showed that the insects were at least 450,000 years old... radioactive dating. "We can fix when the ice was last in contact with the atmosphere," says Jørgen Peder Steffensen... the special isotopes, Beryllium-10 and Chlorine-36 both have a particular half-life of radioactive decay... The relation between them can date when the ice and dust were buried and no longer came in contact with the atmosphere. The dating of dust particles also showed that it has been at least 450,000 years ago... That signifies that there was ice there during the Eemian interglacial period 125,000 years ago. It means that although we are now confronted with global warming, the whole ice sheet will not melt and bring about the tremendous sea-level rises...
Massive Genetic Study Reveals 90 Percent Of Earth's Animals Appeared At The Same Time [06/10/2018]
Greenland Ice Core Analysis Shows Drastic Climate Change Near End Of Last Ice Age [06/19/2008]
The ice core showed the Northern Hemisphere briefly emerged from the last ice age some 14,700 years ago with a 22-degree-Fahrenheit spike in just 50 years, then plunged back into icy conditions before abruptly warming again about 11,700 years ago.
Ice core data supports ancient space impact idea (cosmic impact about 12,900 years ago?) [08/01/2013]
Did Ancient Earth-Chilling Meteor Crash Near Quebec? [09/02/2013]
Ancient Irish texts show volcanic link to cold weather [06/08/2013]
Climate played big role in Vikings' disappearance from Greenland [05/30/2011]
Ancient Supervolcano Affected the Ends of the Earth (Toba, circa 74K ago) [11/08/2012]
The big picture: 65 million years of temperature swings [02/26/2010]